Oil sand bit



W. O. SCOTT OIL SAND BIT Sept. 22, 1931.

Filed Feb. 2, 1931 lllllllllllllllll l I l ll FIG.2

FIG.|

Patented Sept. 22, 1931 llblllli WILLIAM O. SCOTT, F WALNUT PARK, CALIFORNIA oIL SAND BI'r Application filed February 2, 1931.

The object of my invention is to provide a tool. adapted to drill. a hole of enlarged diamete when drilling; in soft formation, as when drilling through oil sand.

My improved bit is adapted to be inserted inside a str'ng of easing, at the end of a drill string and thus lowered to the bottom of the hole. hen the blades rest on the bottom they are automatically spread apart,

forming a iish tail bit of greater width than the diameter of the casing, while the lifting of the drill string causes the blades to fold up so that the bit may be withdrawn.

In the tached drawings, Fig. 1 shows the complete bit in face elevation and 2 in edge elevation, as referred to the position of the bla 3 is a section through the body AA of Fig. 1.

L to fit within the size casing for which the bit is intended, this body having a .dard threaded pin 11 and water channels 12. From this body a stem 13 having the section shown in Fig. 3 extends downwarly in within a similarly shaped opening iormed within a collar 14 which is integral with the upper-end of the blade body 15. 7

Each side of the blade body is slotted for a portion of its length as at 16 and within these slots center blocks l717 are attached to the sliding stem 13, the engagement of these blocks with the ends of the slots limit- 7 the sliding lllOVQIIlQllt of the shaft within Ll e body.

e lower portion of the body is slotted as at 18 for a portion of its length and withl slot are mounted the two blades The upper we blades above the pin, has each on 2EZ(z--22Z of which one face is at 230:23Z). These two projecticn-s or lugs lie face to face within the slot as shown in F 2.

The lower end of stem 13 is relieved on half of its thickness, forming jectf :g lugs 2 ic12ib having or or inner surfaces curved as indi- 25a-25b.

Serial No. 512,950.

curved surfaces 25 of lugs 24. are caused to slide over the curved surfaces 23 of lugs 22 thus forcing the upper ends of the blades inwardly and the lower ends of the blades outwardly. The spread of the blades will obviously be limited by the curvature and the relative travel of these two surfaces.

On lifting the drill string the stem is raised until blocks 17 contact with the upper ends of slots 16, thus lifting the body 15 and permitting the blades to fold into retracted position as their upper edges encounter the casing shoe.

I claim as my invention:

1. An expansion bit having a slotted body and a stem sliding therein, said stem being adapted for attachment to a drill pipe; two blades pivotally mounted within said slotted body, and cooperating lugs on the lower end of said stem and the upper ends of said blades adapted to force the lower ends of said blades apart as said stem is caused to move downwardly within said body by the vertically exerted pressure of the material to be drilled. 5

2. An expansion bit having a slotted body and blades pivotally mounted in said slot; an unthreaded stem slidably mounted within said body, and means whereby a downward movement of said stem in said body causes the stem to cooperate with the upper ends of said blades and the lower ends of said blades to diverge, said movement being made possible by the pressure of the material to go drilled upon the lower end of said slotted 95 ody.

3. In a bit of the class described, a slotted body and a stem adapted to slide therein to a limited extent, said stem bearing upon drill pipe and Water supply channels, the slotted body having pivoted in its lower end two blades pivotally mounted within the body so that the cutting edges project out from the lower part of said body, said blades being provided with lugs above the pivot, shaped so as to stand apart when the cu ters are hanging free, to engage the stem said lugs having bearing surfaces shaped so as to render them capable of being spread apart by the engagement of the said stem and when spread, to force the cutters into a position in which they can cut a hole of larger diameter than the slotted. body, the position of the lugs when the cutters are in cutting position operating to limit the downward travel of the stem.

In Witness that I claim the foregoing I have hereunto subscribed by name this 29th day of September, 1930.

WILLIAM O. SCOTT. 

